The present invention relates to an oil transfer seal assembly that provides multiple pressurized fluid connections between two components of a vehicle transmission.
An oil transfer seal assembly is a transmission part that is used to provide multiple pressurized fluid connections between adjacent components of an automatic transmission. Automatic transmissions have pressurized transmission fluid that is ported according to a transmission control strategy to clutches, valve bodies and pumps. In some instances, adjacent components of the transmission have parallel faces that may define a gap with a high tolerance.
One prior art seal assembly that is designed to operate in this environment is disclosed in U.S. Pat. No. 5,944,360. The device disclosed in the ""360 patent is costly to manufacture because it requires elastomer to be bonded to a plurality of individual tubes. Processing the tubes to prepare them for bonding and removal of flash requires expensive handling and manufacturing steps. The tubes in the ""360 patent must be assembled onto a stamped sheet steel carrier. After initial assembly, the tubes can tip or fall out of the stamped steel carrier during shipment and/or handling causing assembly problems when the transmission is assembled. The tubes can tip once installed in the transmission and could potentially cause a leak.
It would be desirable to provide an oil transfer seal assembly that is inexpensive to manufacture and more robust than the design shown and disclosed in U.S. Pat. No. 5,944,360.
These and other problems and challenges are addressed by the present invention as summarized below.
According to the present invention, an oil transfer seal assembly for a transmission is provided that includes first and second plates having first and second sets of holes, respectively, that are aligned when the first and second plates are assembled together. The holes in the first and second plates each being formed by an axially extending perimeter wall. An elastomeric seal element is bonded to the axially extending perimeter walls of the holes in the first plate. The first plate, second plate, and seal element cooperate to form a plurality of pressurized fluid connections extending through the first and second plates. The perimeter walls of the first and second sets of holes partially overlap and support the seal element as the seal assembly seals the gap between adjacent transmission components.
According to another aspect of the invention, the elastomeric seal element is molded over the inner diameter and outer diameter of the axially extending perimeter walls of the first set of holes in the first plate.
According to other aspects of the present invention, the axially extending perimeter walls of the first plate extend into the second set of holes in the second plate. The axially extending perimeter walls of the second plate may extend from the second plate away from the first plate. The axially extending walls of the first plate and the axially extending walls of the second plate may extend in the same direction. Alternatively, the axially extending walls of the first and second plates may extend toward each other.
According to another aspect of the invention, the elastomeric seal element may have an inner diameter portion lining the perimeter walls of the first set of holes that extends axially through the holes. First and second lips are formed on opposite axial ends of the inner diameter portion of the elastomeric seal element.
According to another aspect of the invention, a method is provided for making an oil transfer seal assembly. The method includes providing first and second plates in which a plurality of holes are formed in corresponding locations. An axially extending perimeter wall is formed on each of the holes in the first and second plates. An elastomeric seal element is molded onto the perimeter wall of the holes in the first plate. The second plate is assembled to the first plate with the axially extending walls of the second plate receiving the axially extending walls of the first plate, with a portion of the elastomeric seal being disposed between the axially extending walls of the first plate and the axially extending walls of the second plate.
According to another aspect of the invention, the holes are formed by punching in a sheet metal forming operation. The axially extending perimeter walls formed on each of the holes may be formed by upsetting the perimeter of each hole in a subsequent sheet metal forming operation.
According to another aspect of the method, the elastomeric seal molding step comprises bonding the elastomeric seal to the plate and forming lips at opposite axial ends of the perimeter walls formed around the holes in the first plate.
According to yet another aspect of the invention, the step of assembling the second plate to the first plate may further comprise radially compressing a portion of the elastomeric seal between axially extending perimeter walls of the first and second plates to retain the second plate on the first plate. The method may also include forming alignment features on either or both of the first and second plates by stamping the plates or over-molding an alignment element in the elastomeric seal portion.
These and other features and aspects of the invention will be better understood in view of the attached drawings and following detailed description of the method and apparatus.